Template for applying samples to a thin layer chromatographic sheet

ABSTRACT

A template for holding a chromatographic sheet while permitting the application of one or a series of liquid samples rapidly and on a well defined area of fixed size comprises a base plate adapted to receive a chromatographic sheet on its surface, an applicator plate mating with the base plate and adapted to lie on the top of the sheet, and means for clamping the parts together to hold the sheet in place. The latter means can include a holding plate which mates with the applicator plate, and suitable means such as bolts for holding the elements together. The applicator plate has one or a series of holes for receiving liquid samples, and the holding plate has corresponding holes overlying the holes in the applicator plate for introduction of the liquid samples. Evaporation of solvent from the samples can be assisted by providing a suitable heater associated with the base plate.

[451 Sept. 11,1973

[ TEMPLATE FOR APPLYING SAMPLES TO A THIN LAYER CHROMATOGRAPHIC SHEET [75] Inventors: Albert D. Baitsholts; Nancy E.

' Jackobs; Imants Timrots, all of Rochester, N.Y.

[73] Assignee: Eastman Kodak Company,

Rochester, N.Y.

[22 Filed: Aug. 31, .1971 211 App]. No: 176,627

Primary Examiner-Samih N. Zaharna Assistant Examiner-Thomas G. Wyse Attorney-William T. French at al.

57 ABSTRACT A template for holding a chromatographic sheet while permitting the application of one or a series of liquid samples rapidly and on a well defined area of fixed size comprises a base plate adapted to receive a chromatographic sheet on its surface, an applicator plate mating with the base plate and adapted to lie on the top of the sheet, and means for clamping the parts together to hold the sheet in place. The latter means can include a holding plate which mates with the applicator plate, and suitable means such as bolts for holding the elements together. The applicator plate has'one or'a series of holes for receiving liquid samples, and the holding plate has corresponding holes overlying the holes in the applicator plate for introduction of the liquid samples.

Evaporation of solvent from the samples can be assisted by providing a suitable heaterassociated with the base plate.

7 Claims, 3 Drawing Figures TEMPLATE FOR APPLYING SAMPLES TO A THIN LAYER CHROMATOGRAPIIIC SHEET BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel apparatus and method for applying a sample to a chromatographic sheet more rapidly than heretofore.

2. The Prior Art The chemical analysis of many compositions has been conducted successfully by spotting the composition on a thin sheet of paper, glass or synthetic resin which carries an adsorbent coating on a surface thereof such a cellulose, silica gel, alumina, powdered nylon, powdered polyethylene, etc. Reference is made to US. Pat. Nos. 3,418,152; 3,418,158; 3,492,155; 3,498,830 for more details. a

After the sheet has been spotted with one spot or a series of spaced spots, it is dipped into a chromatographic eluant solvent such as benzene, alcohols, chloroform, water, etc. and developed in a closed chamber such as that shown in Us. Pat. No. 3,413,842. The solvent migrates along the sheet, carrying the components of the sample spots with it, with individual components travelling at different rates. The components are identifled by comparison with a chromatograph of a known composition.

Usually the spots have been applied by dissolving the unknown composition in a volatile solvent such as methyl or ethyl alcohol, or acetone to form a liquid sample, and then repreatedly dabbing small quantities of the sample on the chromatographic sheet while'allowing solvent to evaporate between dabs. This is a slow expensive procedure, and also is disadvantageous because it is difiicult to confine the sample to a well defined area.

SUMMARY OF THE INVENTION The disadvantages of the prior art are overcome by our novel apparatus which is a template for holding a chromatographic sheet while permitting the application of a liquid sample rapidly and on a well defined area of fixed size. The template can be designed for the application of one or a series of samplesto the chromatographic sheet.

In its broadest aspects our novel apparatus comprises a base plate adapted to receive a chromatographic sheet on its surface, an applicator plate mating with the base plate and adapted to lie on the top of the sheet, and means for clamping the various parts together to hold the chromatographic sheet in place. The latter means can include a holding plate which mates with the applicator plate, and suitable means such as bolts for holding the elements together.

The applicator plate has at least one first hole therein for receiving a liquid sample, and acting as a well; and the holding plate has at least one second hole therein overlying the first hole for introduction therethrough of the liquid sample.

Evaporation of the solvent from the sample to leave a defined dry spot of the substance to be analyzed occurs while it is confined to the well, and may be under ambient conditions or by providing means for heating the apparatus if a greater evaporation rate is desired. Evaporation is also expedited by providing the applicator plate with a plurality of satellite holes surrounding the first hole, through which vapors can pass off.

THE DRAWING THE SPECIFIC EMBODIMENTS Referring to the drawings it will be seen that our novel apparatus comprises a base plate 1 1, and applicator plate 13, and a holding plate 15, all of which are provided with bolt holes for receiving a pair of clamping bolts 17 and 19 which are adapted to be passed through unthreaded holes in-the holding plate and the applicator plate and to be threaded into internally threaded holes 21 and 23 in the base plate. A chromatographic sheet 25 can be positioned between the applicator plate 13 and the base plate 11 and clamped tightly in place by the holding plate 15 and associated clamping bolts. Sheet 25 should be narrow enough to fit between the bolts 17 and 19, or else should be provided with suitable cutouts to accommodate the bolts.

The base plate 11 is a flat metal plate having a planar top surface, and is provided with suitable means for heating the plate, for example, a conventional cylindrical resistance heating element 27 can be positioned in a long bore 28 in the base plate. A rheostat can be provided for regulating the temperature so as to avoid charring or melting the chromatographic sheet.

The applicator plate 13 can be metal or a thin flexible plate of a synthetic resin such as 'Teflori'polytetraholes or bores 31 therethrough which advantageously tric with sample holes 31.

taper from a relatively large diameter at the top to a rel atively smaller diameter at the bottom, thus being frusto conical in shape. The sample holes 31 are arranged in aseries along a straight line so that when samples are to be applied to a chromatographic sheet 25 they are all applied along a straight line parallel to and equidistant from an edge of the sheet. I

Each sample hole 31 is surrounded by a satellite group of holes 33 of much smaller diameter which extend through the applicator plate and are intended to provide for the rapid evaporation of solvent from a liquid sample which has been introduced into the sample hole 31. The satellite holes are cylindrical bores and have their centers arranged on a circle which is concen- To further assist the rapid evaporation of solvent, bottom surface of applicator plate 13 is provided with a shallow annular groove 35 which passes through all of the satellite holes of each sample well, and desirably has a width the same as the diameters of the satellite holes.

The holding plate 15 is a rigid metal plate having a series of cylindrical holes 39 therethrough which register with the sample holes 31, and are of large enough diameter to overlie and expose not only the sample holes 31, but also the satellite holes 33. A liquid sample can be introduced through the holes .39 and into the sample holes 31, while solvent can evaporate off from the samples through the satellite holes 33 and the holes the v When using the apparatus, asshown in FIG. 2, the chromatographic sheet 25 is positioned on base plate 11 with its edge 26 coinciding with an edge of the base plate. The applicator plate 13 is positioned on the top adsorbent coated surface of sheet 25 with the series of sample holes 31 parallel to the edge, the holding plate 15 is positioned on the top of plate 13, and the bolts 17 and 19 are tightened to clamp the whole assembly together. Due to its flexible resilient nature the material of plate 13 seals tightly against the adsorbent coating of sheet 25 at all points around the satellite holes 33 so that the final dried sample spot (after evaporation of all solvent) is defined by the circle of satellite holes and has not been permitted to spread further along the chromatographic sheet.

With this construction there is no longer reason to apply a sample by repeatedly dabbing in onto the surface of a chromatographic sheet over a long period of time, because the full amount of a sample can be introduced at one time and the solvent allowed to evaporate therefrom in one fifth the time or less. When a series of samples are to be analyzed on the same chromatographic sheet they can all be introduced in full volume at the same time through a series of the sample holes 31 and then allowed to dry much more rapidly than was previously possible.

in an examplary apparatus of the type described above the sample holes 31 in the applicator plate 13 are 12 mm apart and are tapered from 6 mm diameter at the top to 2 mm diameter at the bottom, and are'deep enough to hold up to 50 microliters of solution. The satellite drying holes 33 are located with their centers on a circle of 9 mm diameter. As manyas 15 sample holes can be provided in one apparatus for applying samples at spaced points along a chromatographic sheet of centimeters width.

instead of employing the bolts 17 and 19 with holding plate 15 to clamp the parts together, other mechanisms may be used, such as spring type clamps.

Rapid application of samples, as by the above described apparatus and method is of prime importance in clinical laboratories or drug detoxification centers where thousands of samples are chromatographed every week. Where it previously required 5 minutes to apply each sample, using a hot air dryer between dabs of only 2-3 microliters, it is now possible to apply each sample in less than 15 seconds.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

We claim:

1. An apparatus for applying liquid samples to a chromatographic sheet comprising, in combination,

a rectangular base plate adapted to receive a chromatographic sheet on the surface thereof;

a rectangular applicator plate movable into and out of mating engagement with said base plate and adapted to lie on such a sheet, said applicator plate having a plurality of first holes therethrough arranged serially along a straight line parallel to an edge of said applicator plate in spaced relationship to one another, whereby such a chromatographic sheet can be spotted with a plurality of samples; and

means for releasably clamping together said plates to secure such a chromatographic sheet between said base plate and said applicator plate during application of such liquid samples.

2. Apparatus in accordance with claim 1 wherein said applicator plate also has a plurality of additional holes arranged around each of said first holdes for evaporating liquid from said samples.

3. Apparatus in accordance with claim 2 wherein said first holes taper from a relatively large diameter to a relatively smaller diameter adjacent said base plate.

4. Apparatusin accordance with claim 2 wherein said applicator plate also has annular grooves in the surface thereof adjacent said base plate, and passing across the ends of said additional holes, to assist the evaporation of liquid.

5. Apparatus in accordance with claim 1, also comprising means for heating said base plate to assist the evaporation of liquid from said samples.

6. Apparatus in accordance with claim 4, wherein each of said first holes tapers from a relatively large diameter adjacent said holding plate to a relatively smaller diameter adjacent said base plate, said apparatus also comprising means for heating said base plate to assist the evaporation of liquid from said samples.

7. Apparatus in accordance with claim 1 wherein said means for clamping comprises a holding plate mating with said applicator plate and adapted to lie on said applicator plate, said holding plate having a plurality of second holes overlying and corresponding to said first holes, for introduction therethrough of said plurality of samples.

mg UNITED STATES PATENT OFFICE,

CERTIFICATE OF CORRECTION Patent No. 3,757,952 Dated November 5, 1&73

Inventor(s) A; D. Baitsholts, N. E. Jackobs, I. Timrots It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

'- Column 2 line 7 "2-1" should read --2-'2-- Column 2, line 13, after "a" insert --rectangular--; Column 2, line 13, change "and" to --a rectangular"; Column 2, line l t, after "13" insert --which is movable into and out of mating engagement with base plate ll--;

Column 2, line 19, after "base plate" insert "for releasably clamping together plates 11 and l3--; Y 7

Column 2, line 40, after are" insert -spaced from one another and---. n Y

Column I, add the following claim after claim 7:

--8. Apparatus in accordance with claim 1 wherein said first holes taper from a relatively large diameter to a relatively smaller diameter adjacent said base plate.--

On the cover 4 sheet below "Abstract", "7 Claims" should read 8 Claims Signed aha sealed this 5th day of March 1971;.

Attest: v

EDWARD M.FLETCHER,JR C- r hall Dann Attestin Offi 7 Commissioner of Patents 

1. An apparatus for applying liquid samples to a chromatographic sheet comprising, in combination, a rectangular base plate adapted to receive a chromatographic sheet on the surface thereof; a rectangular applicator plate movable into and out of mating engagement with said base plate and adapted to lie on such a sheet, said applicator plate having a plurality of first holes therethrough arranged serially along a straight line parallel to an edge of said applicator plate in spaced relationship to one another, whereby such a chromatographic sheet can be spotted with a plurality of samples; and means for releasably clamping together said plates to secure such a chromatographic sheet between said base plate and said applicator plate during application of such liquid samples.
 2. Apparatus in accordance with claim 1 wherein said applicator plate also has a plurality of additional holes arranged around each of said first holdes for evaporating liquid from said samples.
 3. Apparatus in accordance with claim 2 wherein said first holes taper from a relatively large diameter to a relatively smaller diameter adjacent said base plate.
 4. Apparatus in accordance with claim 2 wherein said applicator plate alSo has annular grooves in the surface thereof adjacent said base plate, and passing across the ends of said additional holes, to assist the evaporation of liquid.
 5. Apparatus in accordance with claim 1, also comprising means for heating said base plate to assist the evaporation of liquid from said samples.
 6. Apparatus in accordance with claim 4, wherein each of said first holes tapers from a relatively large diameter adjacent said holding plate to a relatively smaller diameter adjacent said base plate, said apparatus also comprising means for heating said base plate to assist the evaporation of liquid from said samples.
 7. Apparatus in accordance with claim 1 wherein said means for clamping comprises a holding plate mating with said applicator plate and adapted to lie on said applicator plate, said holding plate having a plurality of second holes overlying and corresponding to said first holes, for introduction therethrough of said plurality of samples. 